1. Field of the Invention
The present invention relates to the field of display technology, and in particular to a liquid crystal display device.
2. The Related Arts
Liquid crystal display (LCD) has a variety of advantages, such as thin device body, low power consumption, and being free of radiation and is thus used in various applications, such as liquid crystal televisions, mobile phones, personal digital assistants (PDAs), digital cameras, computer monitors, and notebook computer screens, placing it in a leading position of flat panel display devices.
Most of the liquid crystal displays that are currently available in the market are backlighting LCDs, which comprise a liquid crystal display panel and a backlight module. The working principle of the liquid crystal display panel is that liquid crystal molecules are filled between a thin-film transistor (TFT) array substrate and a color filter (CF) substrate and a driving voltage is applied to the two substrates to control rotation of the liquid crystal molecules to refract out light from the backlight module to generate an image.
Electro-static discharge (ESD) refers to the movement of electrical charges when objects carrying different electro-static potentials are brought close to and made in direct contact with each other. ESD may generate an instantaneous voltage that is as large as thousands of volts, which often leads to ESD breakdown damage, making a liquid crystal display device unable to operate normally.
To prevent ESD breakdown damage, an ESD test is conducted in the course of manufacturing a liquid crystal display device. Reference being had to FIG. 1, FIG. 1 is a schematic view illustrating a drive structure and an electrostatic test point structure of a conventional liquid crystal display device, which generally comprise a display panel 100, a printed circuit board (PCB) 200, a chip-on-film (COF) 300 that connects the display panel 100 and the PCB 200, a drive integrated circuit (IC) 400 encapsulated in the COF 300, a signal line L100 arranged in the display panel 100, an output line L200 that connects the signal line L100 and the drive IC 400, and a test point TP arranged on the output line L200. During an ESD test, the ESD test is conducted by applying an ESD signal to the test point TP. The test point TP is generally of a shape of square or circle. To protect the static electricity from causing damage to the drive IC 400 and the signal line L100, in the prior art, a transient voltage suppressor (TVS) is often included in the PCB 200 for ESD protection. However, adding the TVS leads to an increase of component costs and also causes bright/dark lines appearing in the panel.
Point or tip discharging refers to electrical discharge occurring at a surface of an object having a relatively great surface curvature, such as a sharp part of an object or a tapering tip of a slender object, under a strong electric field. Generally, a design of an electronic product should avoid the occurrence of tip discharging.